RESUMEN
The resistance of Salmonella to the harsh conditions occurring in shelf-stable dry fermented sausages (DFS) poses a food safety challenge for producers. The present study aimed to model the behaviour of Salmonella in acid (with starter culture) and low-acid (without starter culture) DFS as a function of aw and storage temperature in order to build a decision supporting tool supporting the design of a corrective storage strategy to enhance the safety of DFS. Salmonella spp. were inoculated in the raw meat batter at ca. 6 Log cfu/g with a cocktail of 3 strains (CTC1003, CTC1022 and CTC1754) just before mixing with the other ingredients and additives. After stuffing, sausages were fermented and ripened following industrial processing conditions. Different drying-times were applied to obtain three batches with different aw (0.88, 0.90 and 0.93). Afterwards, DFS were stored at 4, 8, 15 and 25 °C for a maximum of three months and Salmonella spp. were periodically enumerated. The Weibull model was fitted to Log counts data to estimate inactivation kinetic parameters. The impact of temperature and aw on the primary inactivation parameters was evaluated using a polynomial equation. The results of the challenge tests showed that Salmonella spp. levels decreased during storage at all the assayed conditions, from 0.8 Log (in low-acid DFS at 4 °C) up to 6.5 Log (in acid DFS at 25 °C). The effect of both aw and temperature was statistically significant. Delta (δ) parameter decreased by decreasing aw and increasing temperature, while the shape (p) parameter ranged from above 1 (concave) at 10 °C to below 1 at 25 °C (convex). A common secondary model for the p parameter was obtained for each type of DFS, acid and low-acid, indicating that acidification during the production of DFS affected the time for the first Log reduction (δ) during the subsequent storage, but not the overall shape (p parameter) of the inactivation. The developed models covered representative of real conditions, such as Salmonella contamination in the raw materials and its adaptation to the harsh processing conditions. The good predictive performance shown when applying the models to independent data (i.e. up to 80% of the predictions within the 'Acceptable Simulation Zone' for acid sausages) makes them a suitable and reliable risk management tool to support manufacturers to assess and design a lethality treatment (i.e. corrective storage) to enhance the Salmonella inactivation in the product before DFS are released to the market.
Asunto(s)
Alimentos Fermentados/microbiología , Almacenamiento de Alimentos/métodos , Productos de la Carne/microbiología , Salmonella/crecimiento & desarrollo , Animales , Recuento de Colonia Microbiana , Desecación , Fermentación , Manipulación de Alimentos/métodos , Conservación de Alimentos , Productos de la Carne/análisis , Gestión de Riesgos , Porcinos , TemperaturaRESUMEN
A significant amount of the meat is wasted due to spoilage or safety risks. Active packaging systems have a great potential to reduce waste through chemical and microbial control of the product and/or the storage environment. Although commercial products are already available, active packaging is far from being fully developed. In contrast, passive packaging, such as modified atmosphere packaging (MAP) and vacuum packaging, have been fully implemented. Research conducted at the Danish Meat Research Institute (DMRI), demonstrates that it is possible to create new opportunities for the meat industry by modifying MAP or combining microwave treatment with vacuum packaging. Predictive shelf life models can be used to estimate the shelf life in MAP or vacuum under dynamic temperature conditions. Using the tri-gas guidelines, the industry can benefit from the increased eating quality, and the in-package decontamination process using vacuum packaging in combination with 5.8â¯GHz microwaves eliminates C. botulinum spores, resulting in increased food safety and an extended shelf life.
Asunto(s)
Manipulación de Alimentos , Embalaje de Alimentos , Inocuidad de los Alimentos , Carne/normas , Animales , Dinamarca , Conservación de Alimentos/métodos , Carne/microbiologíaRESUMEN
Bologna type sausages were prepared from oxidatively stressed pork (UV-irradiation, 48 h, 5 °C) using a traditional recipe (control) or the same recipe but added green tea extract (500 ppm total phenolic compounds) or rosemary extract (400 ppm total phenolic compounds). Green tea and rosemary extracts protected against formation of TBARS and protein carbonyls. On the contrary, increased thiol loss and a distinct loss of myosin heavy chain and actin due to polymerization by reducible bonds as determined by SDS-page were found by addition of green tea extract. The enhanced protein polymerization was ascribed to the reaction between quinone compounds from the plant extracts and protein thiol groups to yield phenol-mediated protein polymerization. Analysis by ESR spectroscopy revealed increased radical intensities in sausages added plant extracts, which was ascribed to originate from protein-bound phenoxyl radicals, which may protect against other oxidatively induced protein modifications.
Asunto(s)
Camellia sinensis/química , Proteínas en la Dieta/metabolismo , Productos de la Carne/análisis , Estrés Oxidativo , Fenoles/farmacología , Carbonilación Proteica/efectos de los fármacos , Rosmarinus/química , Actinas/metabolismo , Animales , Antioxidantes/farmacología , Productos de la Carne/efectos de la radiación , Cadenas Pesadas de Miosina/metabolismo , Fenoles/metabolismo , Extractos Vegetales/farmacología , Polimerizacion , Quinonas/farmacología , Compuestos de Sulfhidrilo/metabolismo , Porcinos , Sustancias Reactivas al Ácido Tiobarbitúrico , Rayos UltravioletaRESUMEN
The present study evaluated the sensory characteristics of low temperature long time (LTLT) treated Semitendinosus from pork and beef and Pectoralis profundus from chicken. Semitendinosus and Pectoralis profundus muscles were heat treated at 53 °C and 58 °C for T(c) + 6 h, T(c) + 17 h, and T(c) + 30 h (only Semitendinosus from pork and beef). T(c) was the time for the samples to equalize with the temperature in the water bath. Tenderness increased with increasing heating temperature and time in pork and beef, but not in chicken. Juiciness decreased with increasing heating temperature and time in all species, and cooking loss increased with increasing temperature. A done appearance was developed with increasing heating time at 58 °C in pork and beef, while in chicken the done appearance was only affected by temperature. Flavor attributes were less affected by the LTLT treatment for all species.
Asunto(s)
Culinaria , Carne , Temperatura , Mataderos , Animales , Bovinos , Pollos , Color , Manipulación de Alimentos , Masculino , Músculo Esquelético/química , Análisis de Regresión , Porcinos , Gusto , Factores de TiempoRESUMEN
The performance of six predictive models for Listeria monocytogenes was evaluated using 1014 growth responses of the pathogen in meat, seafood, poultry and dairy products. The performance of the growth models was closely related to their complexity i.e. the number of environmental parameters they take into account. The most complex model included the effect of nine environmental parameters and it performed better than the other less complex models both for prediction of maximum specific growth rates (micro(max) values) and for the growth boundary of L. monocytogenes. For this model bias and accuracy factors for growth rate predictions were 1.0 and 1.5, respectively, and 89% of the growth/no-growth responses were correctly predicted. The performance of three other models, including the effect of five to seven environmental parameters, was considered acceptable with bias factors of 1.2 to 1.3. These models all included the effect of acetic acid/diacetate and lactic acid, one of the models also included the effect of CO(2) and nitrite but none of these models included the effect of smoke components. Less complex models that did not include the effect of acetic acid/diacetate and lactic acid were unable to accurately predict growth responses of L. monocytogenes in the wide range of food evaluated in the present study. When complexity of L. monocytogenes growth models matches the complexity of foods of interest, i.e. the number of hurdles to microbial growth, then predicted growth responses of the pathogen can be accurate. The successfully validated models are useful for assessment and management of L. monocytogenes in processed and ready-to-eat (RTE) foods.
Asunto(s)
Comida Rápida/microbiología , Contaminación de Alimentos/análisis , Listeria monocytogenes/crecimiento & desarrollo , Carne/microbiología , Alimentos Marinos/microbiología , Animales , Cinética , Listeria monocytogenes/química , Listeria monocytogenes/aislamiento & purificación , Modelos BiológicosRESUMEN
Water mobility and distribution in fermented sausages produced with differences in pH development as a result of the use of three different starter cultures (T-SPX, F-1, or F-SC-111) and two fermentation temperatures (24 degrees C, or 32 degrees C) were studied using low-field proton NMR relaxometry. Changes in the distribution and mobility of water in fermented sausages upon fermentation and drying were detectable by NMR T(2) relaxation, and the progress in the drying process could be followed as a shift towards faster relaxation times. In addition, the distribution of water in the sausages was significantly affected by the pH decline. The sausages were spiked with Listeria monocytogenes, Salmonella, and Escherichia coli VTEC, and partial least squares regressions revealed that 90% of the variation in reduction of Salmonella and VTEC could be explained by the NMR T(2) relaxation decay. Consequently, the study demonstrated that NMR relaxometry is a promising technique for elucidating process parameters and microbial safety in the production of fermented meat products.